STUDY OF THE PROPER PILE LENGTH IN THE SELF-WEIGHT COLLAPSIBLE LOESS
自重湿陷性黄土地区合理桩长初探

The spatial axisymmetric finite element model is established considering the nonlinear of the soil and the interface between pile and soil. Based on the model,a superposition method is proposed to calculate proper pile length in the self-weight collapsible loess,and it is concluded that,when the distribution of skin friction at the upper and lower parts of soil is of same pattern,added pile length ?L has no significant influence on distribution of skin friction,but it has on ultimate friction resistance. By this method,the influence of property of the self-weight collapsible loess on pile bearing performance is analyzed. It is observed that:(1) when pile is under ultimate capacity,the depth of neutral point is related to pile length,and (2) the influence of collapse coefficient on rest bearing capacity of pile is nonlinear,and (3) the quantitative range of the depth of neutral point and the added pile length is given.